Due to advantages of a small volume, a low power consumption, and radiation-free, a liquid crystal display device (LCD) has become a mainstream product of a flat display device. LCD generally comprises an array substrate and a color film substrate, which are assembled to form a liquid crystal display panel. The array substrate generally comprises thin film transistors and pixel electrodes which are arranged on a glass substrate. The array substrate is further provided with gate lines (i.e., scan lines), data lines and common electrode lines. The gate lines and data lines intersect to divide the array substrate into pixel regions, and each pixel region is provided with a pixel electrode. Gate lines for driving thin film transistors and data lines for delivering voltage signals to be loaded to pixels intersect with one another on the glass substrate.
Channel defects due to foreign materials or residuals form a key factor which affects the yield. Channel defects directly affect normal charging of pixels, thus affect the electrical property of the thin film transistor, and thus affect rotation of liquid crystal. If foreign materials or residuals appear in a large range of the display panel, the display effect of the whole display panel would degrade. The existing repair by cutting generally will damage electrode structure in the thin film transistors, which affects the electrical property of thin film transistors, and further affects display performance of the display panel and display device.